Document the <a-m> shortcut to merge selections

README.asciidoc

@@ -393,6 +393,7 @@ Changes
  * `alt-j`: join selected lines
  * `alt-J`: join selected lines and select spaces inserted
             in place of line breaks
+ * `alt-m`: merge contiguous selections together (works across lines as well)
 
  * `>`: indent selected lines
  * `alt->`: indent selected lines, including empty lines

doc/manpages/shortcuts.asciidoc

@@ -222,6 +222,9 @@ Changes
 *<a-J>*::
 	join selected lines and select spaces inserted in place of line breaks
 
+*<a-m>*::
+	merge contiguous selections together (works across lines as well)
+
 *>*::
 	indent selected lines